JP2008292295A - Speedometer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a walking speed measurement, without basing on the length of stride. <P>SOLUTION: A detection circuit 101 is used by a user wearing on the leg part, an acceleration sensor unit 106-108 output acceleration signals, at a level corresponding to the acceleration generated by walking, and a walking pulse detection unit 121 outputs a walking pulse signal. A processing unit 103 calculates a relation formula among the walking speed of the user, acceleration signal and walking pitch, which is recorded in a memory unit 105. The processing unit 103 receives the acceleration signal and walking pulse and calculates the walking speed of the user, by using the acceleration signal, walking pitch and the relation formula stored in the memory unit 105. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a speedometer for measuring a moving speed of a user.

Conventionally, an acceleration sensor has been used as a sensor for measuring the number of steps, and the number of steps is obtained from a signal from vertical acceleration or landing impact output from the acceleration sensor, multiplied by a predetermined step length, The technique for obtaining the moving speed has been known for a long time.
However, it is relatively easy to accurately determine the number of steps, but it is difficult to set an accurate stride.

In order to accurately determine (set) the stride, the following techniques have been proposed.
For example, Patent Document 1 discloses an invention in which the stride is adjusted according to the pitch in order to improve the accuracy of the moving distance obtained by the number of steps × the stride.
Further, Patent Document 2 discloses an invention in which a correlation between acceleration and stride is used, an accurate stride is obtained from acceleration, and a movement distance is obtained by multiplying the step count.

As described above, the inventions described in Patent Documents 1 and 2 are configured to calculate the speed based on the stride.
However, although both “pitch and stride” and “acceleration and stride” have a certain degree of correlation, sufficient accuracy cannot be obtained with respect to stride if conditions are limited or the correlation is weak. Therefore, there is a problem that it is difficult to obtain an accurate speed based on the stride.

JP 7-333000 A JP-A-9-152355

  An object of the present invention is to make it possible to measure a moving speed without being based on a stride.

  According to the present invention, the acceleration sensor means that is used by being mounted on the leg of the user and outputs an acceleration signal at a level corresponding to the acceleration generated by the movement of the user, the moving speed of the user, and the acceleration signal And a relational expression calculating means for calculating a relational expression of the movement pitch, a storage means for storing at least the relational expression, a pitch calculating means for calculating the movement pitch of the user based on the acceleration signal, and the measurement mode in the measurement mode Speed calculation means for receiving an acceleration signal from an acceleration sensor means and calculating the user's movement speed using the acceleration signal, the movement pitch calculated by the pitch calculation means, and the relational expression stored in the storage means; A speedometer is provided that is characterized by comprising.

  The relational expression calculating means calculates a relational expression of the user's moving speed, acceleration signal, and moving pitch. The storage means stores at least the relational expression. The pitch calculation means calculates the movement pitch of the user based on the acceleration signal from the acceleration sensor means. The velocity calculation means receives an acceleration signal from the acceleration sensor means in the measurement mode, and uses the acceleration signal, the movement pitch calculated by the pitch calculation means, and the movement of the user using the relational expression stored in the storage means. Calculate the speed.

Here, the relational expression calculating means is configured to determine the relation based on a relation between the level of the acceleration signal obtained by the user moving at a predetermined speed and a predetermined movement pitch, and the movement speed and the pitch. You may comprise so that a formula may be calculated.
In the preliminary mode, the relational expression calculating means includes an average value of the acceleration signal level obtained by the user moving a plurality of times at a predetermined speed and a predetermined movement pitch, and the movement speed and pitch. The relational expression may be calculated based on the relationship between

Further, the relational expression is Y = aX + bZ + c (where Y is an average moving speed, X is an average value of acceleration signal level, Z is a moving pitch, a, b and c are constants), and the relational expression calculating means includes: The constants a, b, and c may be calculated based on three measurement results.
The acceleration sensor means may include a plurality of acceleration sensors having different sensitivity axes.

Further, at least the acceleration sensor means may be configured to be used by being worn on the user's foot.
Moreover, it may have a display means for displaying the speed, and the display means may be configured to be used by being worn on an arm.
Further, it may be configured to include a step number calculating means for calculating the number of steps based on an acceleration signal from the acceleration sensor means.

  According to the present invention, it is possible to measure the moving speed without being based on the stride.

First, the basic concept for speed measurement in the speedometer according to the embodiment of the present invention will be described. In the speedometer according to the present embodiment, an acceleration sensor is used to measure the walking speed of the user.
FIG. 7 is a diagram illustrating a mounting portion of the acceleration sensor used in the present embodiment.

At least the acceleration sensor 703 is used by being mounted on a leg portion (a body part from the toe to the thigh) 702 of the user 701. FIG. 7 shows a state where the acceleration sensor 703 is mounted on the back of the foot 705.
The walking speed calculated based on the acceleration signal from the acceleration sensor 703 is displayed by the display unit 704 attached to the wrist by wireless transmission or the like.

  FIG. 8 is a characteristic diagram showing the relationship between the walking pitch and the average value (average acceleration) of a predetermined time (for example, 60 seconds) of the acceleration signal output from the acceleration sensor. FIG. 8 shows an example in which the user 701 walks at three different speeds with the acceleration sensor 703 mounted on the back of the foot 705 (see FIG. 7). Characteristics 801 to 803 are characteristics when walking at walking speeds of 4 km / h, 5 km / h, and 6 km / h, respectively.

As can be seen from FIG. 8, even when the walking pitch changes, there is a high correlation between the average acceleration and the walking speed.
The speedometer according to the present embodiment has a high correlation between the average value of acceleration output from the acceleration sensor for a predetermined time and the moving speed of the user, and this correlation limits the mounting site of the acceleration sensor to the legs. This is based on the knowledge that it does not depend on the walking pitch.
The characteristics shown in FIG. 8 are measured with the acceleration sensor 703 mounted on the back of the foot 705 of the user 701. However, the characteristic is directly applied to any part of the leg 702 from the toe to the thigh. It is considered that the same result can be obtained even if it is worn indirectly by wearing it on clothes or shoes.

Hereinafter, the speedometer according to the embodiment of the present invention will be described.
FIG. 1 is a block diagram of a speedometer according to an embodiment of the present invention.
In FIG. 1, the speedometer is configured by a detection unit 101 that detects a user's walking and outputs an acceleration signal at a level corresponding to the acceleration, an operation switch, and the like, and performs various operations such as a speed measurement start operation. Unit 102, processing unit 103 that performs a walking speed calculation process based on the acceleration signal from detection unit 101, display unit 104 that displays the measured walking speed and the number of steps, storage unit 105, oscillation unit 120, walking pulse detection Part 121 and speaker 122 are provided.

The detection unit 101 includes a plurality of (three in this embodiment) acceleration sensor units 106 to 108 having acceleration sensors 109, 111, and 113 having different sensitivity axes (different from each other by 90 degrees in this embodiment). I have.
The acceleration sensor unit 106 has an axis of sensitivity in the X-axis direction and outputs an acceleration signal in an analog format having a signal level corresponding to the acceleration. The acceleration sensor unit 106 samples the acceleration signal from the acceleration sensor 109 to analog / digital ( A / D) includes an acceleration level detection unit 110 that converts and outputs a digital acceleration signal of a corresponding signal level.

  The acceleration sensor unit 107 has a sensitivity axis in the Y-axis direction and outputs an analog acceleration signal having a signal level corresponding to the acceleration, and the acceleration signal from the acceleration sensor 111 is analog / digital (A / D). An acceleration level detection unit 112 that converts and outputs a digital acceleration signal of a corresponding signal level is provided.

Similarly, the acceleration sensor unit 108 has a sensitivity axis in the Z-axis direction and outputs an acceleration signal in an analog format having a signal level corresponding to the acceleration. The acceleration signal from the acceleration sensor 113 is analog / digital (A / D) An acceleration level detector 114 that converts and outputs a digital acceleration signal of a corresponding signal level is provided.
In addition, a walking pulse detection unit 121 that outputs a walking pulse signal corresponding to walking based on an acceleration signal from the acceleration sensor 113 is connected to the output unit of the acceleration sensor 113.

The processing unit 103 is configured by a central processing unit (CPU).
The storage unit 105 includes a ROM that stores a program executed by the processing unit 103 and a RAM that is used as a work area or the like when the processing unit 103 executes the program. In the RAM of the storage unit 105, a speed calculation formula storage area 115 for calculating a speed based on an acceleration signal from the detection unit 101, a speed data storage area 116, and acceleration data 1, 2, 3 at a specific speed are stored. Storage areas 117, 118, and 119 are provided. Although not shown, a data storage area for storing data such as the number of steps and the pitch is provided.

The oscillating unit 120 generates a clock signal that serves as a reference for the time measuring operation. The processing unit 103 can measure time such as walking time based on the clock signal from the oscillation unit 120 in accordance with the operation of the input unit 102.
The display unit 104 can be configured to be connected to the processing unit 103 by wire, but may be configured to be connected to the processing unit 103 wirelessly as described in FIG.
Under the control of the processing unit 103, the speaker 122 performs a reporting operation such as outputting a pitch sound at a predetermined frequency in the preliminary mode or outputting an alarm sound in the preliminary mode or the measurement mode.

  Here, the detection unit 101, the display unit 104, the storage unit 105, and the speaker 122 constitute an acceleration sensor unit, a display unit, a storage unit, and a sound report unit, respectively. The processing unit 103 constitutes relational expression calculation means and speed calculation means. Further, the processing unit 103 and the walking pulse detection unit 121 constitute a step count calculation unit and a pitch calculation unit.

The acceleration sensor means is used by being mounted on the leg of the user, and can output an acceleration signal at a level corresponding to the acceleration generated by walking.
The relational expression calculating means can calculate a relational expression of the user's walking speed, the acceleration signal, and the walking pitch in the preliminary mode. The storage means can store at least the relational expression.

The pitch calculation means can calculate the walking pitch of the user based on the acceleration signal.
The speed calculation means receives an acceleration signal from the acceleration sensor means in the measurement mode, and uses the acceleration signal, the walking pitch calculated by the pitch calculation means, and the relational expression stored in the storage means, The walking speed can be calculated.
The display means can display the speed as well as the number of steps and / or the pitch, and can be configured to be worn on the arm, for example.
The sound reporting means can output a pitch sound at a predetermined frequency in the preliminary mode.

FIGS. 2 and 3 are flowcharts showing processing in a mode (preliminary mode) for obtaining constants used in relational expressions of average speed, average acceleration signal level, and walking pitch. This process is mainly performed by loading the program stored in the ROM of the storage unit 105 into the RAM of the storage unit 105 and executing it by the processing unit 103.
4 and 5 are diagrams showing display contents on the display unit 104 in the preliminary mode.
Hereinafter, the operation in the preliminary mode will be described with reference to FIGS.

First, the user attaches at least the acceleration sensors 109, 111, and 113 to the back of his / her foot and operates the input unit 102 to start the operation in the preliminary mode.
In response to the preliminary mode start operation by the input unit 102, the processing unit 103 controls the display unit 104 to perform the display of FIG.
The user views the display on the display unit 104 and presses the button on the input unit 102 to input measurement start in the preliminary mode.

  When the processing unit 103 detects the start of measurement in the preliminary mode (step S201), the speaker 122 reports a pitch sound 1 having a frequency corresponding to a pitch value 1 (eg, 110 times / minute corresponding to a pitch of 110 steps / minute). Control is performed to start the sound (step S202). At the same time, the processing unit 103 starts a time counting operation based on the clock signal from the oscillation unit 120 (step S203).

The user starts walking at an average speed of 4 km / h in accordance with the pitch sound 1 output from the speaker 122.
In addition, with the start of the preliminary mode, each acceleration sensor 109, 111, 113 also starts the walking detection operation and outputs an analog acceleration signal having a signal level corresponding to the acceleration.
When the processing unit 103 detects the measurement start and starts measurement, the processing unit 103 controls the display unit 104 to switch to the display during measurement shown in FIG.

  When the sampling timing set to occur at a predetermined cycle arrives (step S204), the processing unit 103 samples the acceleration signals from the acceleration sensors 109, 111, and 113 by the corresponding acceleration level detection units 110, 112, and 114. Control to output. Each acceleration level detection unit 110, 112, 114 converts the acceleration signal from the corresponding acceleration sensor 109, 111, 113 into an acceleration signal in a digital signal format and outputs the acceleration signal.

The processing unit 103 detects digital acceleration signals from the respective acceleration level detection units 110, 112, and 114, and measures the acceleration level (step S205). At this time, assuming that the levels of the acceleration signals output from the acceleration level detection units 110, 112, and 114 are XA, YA, and ZA, the acceleration level is calculated by the following equation.
Acceleration level = √ (XA ² + YA ² + ZA ² )
In this embodiment, since the three acceleration sensors 109, 111, and 113 are used, the acceleration level is calculated by the above formula. However, an appropriate formula is appropriately used according to the number of acceleration sensors to be used, conditions, and the like. Can be used to calculate.

Next, the processing unit 103 adds 1 to the count value of the internal counter (not shown) (step 206). The count value of the counter corresponds to the number of acceleration signals measured from one acceleration level detection unit.
Next, the processing unit 103 adds the acceleration level measured this time to the integrated acceleration level value stored in the storage unit 105, and stores the new integrated acceleration level value in the storage unit 105 (step S207). .

Unless the user inputs a measurement stop instruction from the input unit 102, the processing unit 103 returns to the processing step S203 and repeats the processing (step S208).
When the user walks for 1 minute, the user operates the input unit 102 to input a measurement stop instruction. When the processing unit 103 determines in step S208 that the user has input a measurement stop instruction from the input unit 102, the processing unit 103 ends the time measuring operation (step S209). At the same time, the processing unit 103 controls the display unit 104 to switch to the measurement end display in FIG.

Next, the processing unit 103 calculates an average acceleration level 1 per unit time based on the measured time and the acceleration level integrated value (step S210). At this time, the processing unit 103 calculates the average acceleration level 1 by the following equation.
Average acceleration level 1 = acceleration level integrated value / count value of counter Next, the processing unit 103 associates the calculated average acceleration level 1, average speed 1 and pitch value 1 with each other as storage data 1 at a specific speed. 105, and the first measurement process is terminated (step S211).

Subsequently, the processing unit 103 controls the display unit 104 to perform the display of FIG.
The user views the display on the display unit 104 and presses the button on the input unit 102 to input the second measurement start in the preliminary mode, and the frequency corresponding to the pitch value 2 (for example, the same pitch as the first time). Control is performed so as to start reporting sound of pitch sound 2 of 110 times / minute corresponding to 110 steps / minute (step S202). At the same time, the processing unit 103 starts a time counting operation based on the clock signal from the oscillation unit 120 (step S203).

The user starts walking at an average speed of 6 km / h in accordance with the pitch sound 2 output from the speaker 122.
When detecting the second measurement start in the preliminary mode, the processing unit 103 performs the same process as the first measurement, and calculates the average acceleration level 2 per unit time by the following equation.
Next, the processing unit 103 associates the calculated average acceleration level 2, the average speed 2 and the pitch value 2 with each other and stores this in the storage area 118 of the storage unit 105 as the acceleration data 2 at the specific speed, for the second measurement. The process ends (steps S201 to S211).
Average acceleration level 2 = acceleration level integrated value / counter value

The third measurement is performed in the same manner as the second time (steps S201 to S211). In the case of the third time, the same display as in FIGS. 5A to 5C is made on the display unit 104, but the pitch sound has a frequency corresponding to a pitch value 3 different from the pitch values 1 and 2 (for example, A pitch sound 3 of 130 times / minute corresponding to a pitch of 130 steps / minute is output (step S202). The walking speed is the same as the second time.

When detecting the third measurement start in the preliminary mode, the processing unit 103 performs the same process as the second measurement, and calculates an average acceleration level 3 per unit time by the following equation.
Next, the processing unit 103 associates the calculated average acceleration level 3, the average speed 3 and the pitch value 3 with each other, and stores this in the storage area 119 of the storage unit 105 as the acceleration data 3 at the specific speed for the third measurement. The process ends.
Average acceleration level 3 = acceleration level integrated value / counter value

Subsequently, the processing unit 103 refers to the acceleration data 1 to 3 at the specific speed stored in the storage unit 105 (steps S301 to S303 in FIG. 3), calculates constants a, b, and c of the following speed calculation formula, A speed calculation formula is determined (step S304).
Average speed = a × average acceleration level + b × pitch value + c
Since the relational expression of the average speed, the average acceleration level, and the pitch value is obtained in this way, the processing unit 103 thereafter uses the speed calculation expression to determine the user based on the acceleration signal from the detection unit 101. The average walking speed can be calculated.

  The processing unit 103 stores the speed calculation formula in the storage area 115 of the storage unit 105 (step S305). Note that only the constants a, b, and c may be stored in the storage unit 105, a predetermined calculation process may be performed using the constants, and as a result, the same calculation as the speed calculation formula may be performed. As described above, the storage unit 105 can be configured to store at least constants used in the relational expression of the user's walking speed, acceleration signal, and walking pitch.

  FIG. 6 is a flowchart showing processing in a mode (measurement mode) in which the walking speed is measured using the speed calculation formula determined as described above. This process is mainly performed by loading the program stored in the ROM of the storage unit 105 into the RAM of the storage unit 105 and executing it by the processing unit 103.

First, similarly to the preliminary mode, the user attaches at least the acceleration sensors 109, 111, and 113 to the back of his / her foot and operates the input unit 102 to start the measurement mode operation and start walking.
When the processing unit 103 detects a measurement start instruction from the input unit 102 (step S601), the processing unit 103 starts a measurement operation.

As a result, each acceleration sensor 109, 111, 113 starts to operate and outputs an analog acceleration signal having a signal level corresponding to the acceleration generated by walking.
The processing unit 103 ends the process when the measurement end (stop) instruction by the input unit 102 is detected (step S602), but determines that the sampling timing has arrived when the instruction is not detected. (Step S603).
When the processing unit 103 determines in step S603 that the sampling timing has not arrived, the processing unit 103 determines whether or not the walking pulse detection unit 121 detects walking and outputs a corresponding walking pulse signal (step S615). .

If the processing unit 103 determines that the walking pulse detection unit 121 has output a walking pulse signal, the processing unit 103 adds 1 to the count value of a step counter (not shown) that counts the number of steps in the processing unit 103, and processing step The process returns to S602 (step S616).
When the processing unit 103 determines in step S615 that the walking pulse detection unit 121 has not output the walking pulse signal, the processing unit 103 directly returns to processing step S602.

On the other hand, when the processing unit 103 determines that the sampling timing has come in processing step S603, the corresponding acceleration level detection units 110, 112, and 114 sample and output the acceleration signals from the respective acceleration sensors 109, 111, and 113. To control.
The processing unit 103 detects the digital acceleration signal from each of the acceleration level detection units 110, 112, and 114, and measures the acceleration level in the same manner as the processing step S205 (step S604). It should be noted that, as described above, the calculation can be performed using an appropriate expression according to the number of acceleration sensors to be used, conditions, and the like.

Next, the processing unit 103 adds the acceleration level measured this time to the integrated acceleration level value stored in the storage unit 105, and stores the new integrated acceleration level value in the storage unit 105 (step S605). .
Next, the processing unit 103 adds 1 to the count value of the internal counter (step 606). The count value of the counter corresponds to the number of acceleration signals measured from one acceleration level detection unit.

When determining that the average acceleration measurement timing has occurred (step S607), the processing unit 103 calculates the average acceleration level per unit time based on the acceleration level integrated value stored in the storage unit 105 and the count value of the counter (step S607). Step S608). The average acceleration measurement timing can be configured to occur every time the count value of the counter reaches a predetermined value.
Next, the processing unit 103 resets the counter to make the count value zero (step S609).

Next, the processing unit 103 calculates a pitch value per unit time based on the walking pulse signal from the walking pulse detection unit 121 (step S610), and then resets the count value of the step counter to zero (step S611). ).
Subsequently, the processing unit 103 refers to the speed calculation formula (step S612), and calculates the average speed by substituting the average acceleration level and pitch value into the speed calculation formula (step S613).

  The processing unit 103 outputs the calculated average speed information to the display unit 104 (step S614), and controls the display unit 104 to display the speed. As a result, the average speed of the user is displayed on the display unit 104. In addition, the processing unit 103 responds to an instruction from the input unit 102 and calculates the pitch calculated based on the walking signal from the detection unit 101 (in other words, based on the walking pulse signal of the walking pulse detection unit 121). Control is performed so that the number of steps is displayed on the display unit 104. Thereby, the display unit 104 displays the number of steps, the pitch, and the like.

  As described above, in the speedometer according to the present embodiment, the detection circuit 101 is used while being worn on the user's foot, and outputs an acceleration signal at a level corresponding to the acceleration generated by walking. In the preliminary mode, the processing unit 103 calculates a relational expression of the walking speed of the user, the acceleration signal from the detection circuit 101, and the walking pitch and stores the relational expression in the storage unit 105. In the measurement mode, the processing unit 103 receives the acceleration signal and the walking pulse signal from the detection circuit 101, and calculates the walking speed of the user using the acceleration signal and the relational expression stored in the storage unit 105. To do.

Therefore, the walking speed can be measured without being based on the stride.
In addition, since walking speed is calculated based on acceleration signals generated during walking, it is possible to measure walking speed with higher accuracy than conventional speedometers that calculate walking speed based on the number of steps and the set step length. is there.
In addition, it is not necessary for the user to set the stride in advance, and it is possible to realize a highly accurate speedometer that is not affected by the walking state during walking (intentional stride change).

In this embodiment, the example of walking speed has been described. However, the present invention is not limited to walking, but can be applied to measurement of moving speed at which a user moves, such as running.
In addition, it is not necessary to configure the entire speedometer as one unit, and considering the convenience of the user, the transmission unit equipped with the acceleration sensor and the reception unit equipped with the display unit may be configured as separate devices. Is possible. In this case, a wireless communication system can be used as a system for transmitting data from the transmission unit to the reception unit.

  In addition, depending on the type of transmission data, the processing content of the processing unit can be appropriately divided and mounted on the transmission unit and the reception unit, respectively.

  It can be applied to a speedometer that is mounted on a leg of a user and measures the moving speed of the user. It can also be used as a speedometer in combination with other devices such as an electrocardiograph and a pedometer.

It is a block diagram of the speedometer which concerns on embodiment of this invention. It is a flowchart which shows the process of the speedometer which concerns on embodiment of this invention. It is a flowchart which shows the process of the speedometer which concerns on embodiment of this invention. It is explanatory drawing which shows the display content of the speedometer which concerns on embodiment of this invention. It is explanatory drawing which shows the display content of the speedometer which concerns on embodiment of this invention. It is a flowchart which shows the process of the speedometer which concerns on embodiment of this invention. It is a figure which shows the mounting part of the acceleration sensor used for embodiment of this invention. It is a characteristic view which shows the relationship of the pitch-average acceleration in embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 ... Detection part 102 ... Input part 103 ... Processing part 104 ... Display part 105 ... Storage part 106-108 ... Acceleration sensor part 109, 111, 113 ... Acceleration sensor 110 , 112, 114... Acceleration level detectors 115 to 119... Storage area 120... Oscillator 121.

Claims (8)

Acceleration sensor means that is used by being mounted on a user's leg and outputs an acceleration signal of a level corresponding to the acceleration caused by the movement of the user;
Relational expression calculating means for calculating a relational expression of the user's moving speed, acceleration signal and moving pitch using the acceleration sensor means;
Storage means for storing at least the relational expression;
Pitch calculating means for calculating the movement pitch of the user based on the acceleration signal;
Speed calculation means for receiving an acceleration signal from the acceleration sensor means and calculating the user's movement speed using the acceleration signal, the movement pitch calculated by the pitch calculation means, and the relational expression stored in the storage means; A speedometer characterized by comprising:   The relational expression calculation means calculates the relational expression based on the relationship between the level of the acceleration signal obtained by the user moving at a predetermined speed and a predetermined movement pitch, and the movement speed and the pitch. The speedometer according to claim 1, wherein:   The relational expression calculating means is based on the relationship between the average value of the acceleration signal level obtained by the user moving a plurality of times at a predetermined speed and a predetermined movement pitch, and the movement speed and the pitch. The speedometer according to claim 1 or 2, wherein a relational expression is calculated.   The relational expression is Y = aX + bZ + c (where Y is the average moving speed, X is the average value of the acceleration signal level, Z is the moving pitch, a, b and c are constants), and the relational expression calculating means is three times The speedometer according to any one of claims 1 to 3, wherein the constants a, b, and c are calculated based on the measurement results.   The speedometer according to any one of claims 1 to 4, wherein the acceleration sensor means includes a plurality of acceleration sensors having different sensitivity axes.   The speedometer according to any one of claims 1 to 5, wherein at least the acceleration sensor means is used while being attached to a foot portion of the user.   The speedometer according to claim 1, further comprising display means for displaying the speed, wherein the display means is used while being worn on an arm.   The speedometer according to claim 1, further comprising a step count calculating unit that calculates a step count based on an acceleration signal from the acceleration sensor unit.

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